Finders Keepers

On the lowest level you can collect unlimited bombs by purchasing, entering into the next level, ending game and then restart. You always get all your money back and the bombs just keep adding up. You can do the same to get the preferred items to use on the next level but you don't have to reenter the game each time to change the items you can pick from to buy. Only for bombs to get them, you have to enter the next level and then exit to accumulate extra bombs.